The invention relates to an abrasive article, and a method of making and using the abrasive article. Abrasive articles have been utilized to abrade and finish workpiece surfaces for well over a hundred years. These applications have ranged from high stock removal, and high pressure metal grinding processes to fine polishing of ophthalmic lenses and primed surfaces. In general, abrasive articles comprise a plurality of abrasive particles bonded either together (e.g., a bonded abrasive or grinding wheel) or to a backing (e.g., a coated abrasive). For a coated abrasive there is typically a single, or sometimes two layers of abrasive particles. Once these abrasive particles are worn, the coated abrasive is essentially worn out and is typically discarded.
One way to extend the life of a coated abrasive has been to use a three-dimensional coating. A three-dimensional coating of abrasive particles is exemplified in U.S. Pat. No. 5,152,917 (Pieper et al.). Pieper reports a three-dimensional structured abrasive that results in a relatively high rate of cut and a relatively fine surface finish on the workpiece surface. The abrasive comprises non-random, precisely shaped abrasive composites that are bonded to a backing.
One method of providing a three-dimensional, textured, fixed abrasive article is generally as follows. A slurry containing a mixture of a binder precursor and a plurality of abrasive particles is coated onto a production tool having cavities that are the negative of the desired shape of the textured surface. A backing is brought into contact with the exposed, coated surface of the production tool such that the slurry wets the surface of the backing. Then, the binder may be first at least partially solidified, cured, or gelled. The abrasive article is then removed from the production tool and subsequently fully cured if it was not fully cured in the previous first cure. Alternatively, the slurry may be applied onto the surface of the backing and then the production tool may be brought into contact with the slurry coated on the backing. The abrasive layer thus comprises a plurality of abrasive “composites” on a backing.
A two-step curing process comprising a first partial cure and a subsequent full cure is known as a dual cure process. In a dual cure system, the polymerization or crosslinking of the binder precursor occurs in two separate stages, via either the same or different reaction mechanisms. Traditionally, chemical curing mechanisms that may occur in these systems include radical polymerization of acrylic double bonds, radical polymerization of unsaturated polyesters, styrene or other monomers, and cationic curing of vinyl ethers or epoxies. The dual-cure systems may combine radiation curing with thermal curing, or radiation curing with moisture curing, for example. Combining curing mechanisms has been accomplished in the past, for example, by mixing materials with two types of functionality on one structure or by mixing different materials having one type of functionality. Such systems are discussed in Peeters, “Overview of Dual-Cure and Hybrid-Cure Systems in Radiation Curing,” Radiation Curing in Polymer Science and Technology: Volume III Polymer Mechanisms, Fouassier and Rabek, eds., Elsevier Applied Science, NY, Chapter 6, 177-217 (1993).
However, using past dual cure systems may lead to inconsistent cure throughout the thickness of a three-dimensional abrasive article. A major concern in the manufacture of abrasive articles is product consistency.